U.K.-based postal service firm Royal Mail has been impacted by a "cyber incident" that has prevented overseas delivery of parcels and letters, ZDNET reports. Letters and parcels sent from overseas have also faced slight delays stemming from the intrusion, which has not affected deliveries within the U.K. "Our teams are working around the clock to resolve this disruption and we will update customers as soon as we have more information. We immediately launched an investigation into the incident and we are working with external experts. We have reported the incident to our regulators and the relevant security authorities," said the Royal Mail, which sought a pause in the posting of items for delivery abroad amid an ongoing investigation into the incident. No other details have been provided regarding the incident but the U.K.'s National Cyber Security Centre has already been notified. "We are aware of an incident affecting Royal Mail Group Ltd and are working with the company, alongside the National Crime Agency, to fully understand the impact," said NCSC.